The format and the contents of the attribution line can be changed by users by defining a 'custom attribution line'. The custom attribution line is a text with some special variables. The default attribution line uses following definition:

%n%nOn %a, %d %b %Y %H:%M %z, %+f wrote:

The system will replace any %X sequence with certain values.

Following sequences are defined:

Sender Details:

%+f - the sender's name and email address

%+n - the sender's name (or email address, if no name is defined)

%+a - the sender's email address

Time Formatting:

%d - the day of the month when the message was sent (01-31)

%e - the day of the month when the message was sent (1-31)

%m - the month when the message was sent (01-12)

%Y - the year when the message was sent (4 digits)

%y - the year when the message was sent (last 2 digits)

%H - the hour when the message was sent (00-23)

%I - the hour when the message was sent (01-12)

%k - the hour when the message was sent (0-23)

%l - the hour when the message was sent (1-12)

%p - 'AM' or 'PM' when when the message was sent

%P - 'am' or 'pm' when when the message was sent (yes, they're back to front. [1])